Still using a 32-bit Windows machine? Here’s how to remove the 4GB limit that might be hampering your RAM usage.

While 32-bit was once the standard, in recent years more and more Windows users have migrated to the 64-bit version of the OS. However, there are still some holdouts using 32-bit systems — and they might well be missing out on some of the potential of their hardware if they haven’t addressed a known issue with RAM on that sort of machine.

Why Am I Limited to 4GB of RAM?

The reason behind the so-called ‘3GB barrier’ lies in the architecture of 32-bit operating systems. Each individual byte of RAM has its own physical address that the system uses to access particular units of memory. 32-bit systems have a limit on the amount of addresses available for RAM and various other components. Depending on your setup, this can limit the amount of RAM your system can support to somewhere around 3GB — although it could be slightly higher or slightly lower.

A technique called physical address extension, or PAE, can allow a 32-bit OS to support up to 64GB of RAM. By increasing the physical address size from 32 bits to 36, there are plenty more addresses available for the system to use — but the system’s virtual addresses stay the same, ensuring that everything works just as it should.

How Can I Tell If I Need PAE?

Whether or not you need to utilize PAE will come down to two important factors; are you running a 32-bit or 64-bit version of Windows, and how much of your installed RAM is usable? To establish both, open up Control Panel, and navigate to System and Security > System.

How to Enable PAE on Windows 7 and Windows 8

First things first, download PatchPae2 from wj32. This will give you a .zip file containing a patch that will work for machines running either Windows 7 or Windows 8/8.1, but there’s a few slight differences between the processes for versions of the OS pre- and post- Windows 8. Start by unzipping the file you downloaded and placing it in a folder inside Windows > System32, which will likely be found on your computer’s C: drive. Once PatchPae2.exe is in place, make a note of its file path, as you’ll need this later on.

Now, open a Command Prompt with Administrator privileges enabled. You can do this easily by searching your system for Command Prompt, and then right-clicking the correct entry in the search results and choosing to Run as Administrator. You should be presented with the standard command line interface — ensure that the directory reads system32.

Next, patch the loader to disable digital signature verification by entering the command PatchPae2.exe -type loader -o winloadp.exe winload.exe. Then, create a new boot option with the following input: bcdedit /copy {current} /d “Windows (PAE Patched)”. The phrase between the quotation marks is simply a comment for you to label what you’ve done.

You should see a message that tells you that the copy was successful, and gives you a unique boot ID in the format {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}. Copy that ID, because we’re going to use it for the next few commands. Enter bcdedit /set {boot ID} kernel ntoskrnx.exe if you’re using Windows 8 or 8.1, and bcdedit /set {boot ID} kernel ntkrnlpx.exe for anything earlier.

There are just a few more commands that we need to run. First, make sure our patched loader is selected by inputting bcdedit /set {boot ID} path \Windows\system32\winloadp.exe. Then, use bcdedit /set {boot ID} nointegritychecks 1 to confirm that the loader shouldn’t be verified. Then, set this boot entry as the default with bcdedit /set {bootmgr} default {boot ID}. You can also use bcdedit /set {bootmgr} timeout X to set a custom boot menu display time by replacing X with your desired length of time in seconds, but this is optional. All that’s left from this point is to restart your computer.

really tanks, you save my windows, i should installed win7 64 bit, and with your solution ,now i don't need and i use all of my 8 GB of ram, tanks for saving my software, many thanks, i want to help and I want compensate, how can i? please just tell me, 1000 times thank you....

im using win7 and when i try to use bcdedit /copy {current} /d “Windows (PAE Patched)” it tell me " C:\Windows\system32>bcdedit /copy {current} /d "Windows (PAE Patched)"
A description for the new entry must be specified.
Run "bcdedit /?" for command line assistance.
The parameter is incorrect. "

This patch work only if you do not using windows update. Microsoft released some updates which modifies kernel, so patch cant be applied to it. One or two was somewhere 2014 fall, and another one march 2015 or so, after which I fully disabled windows update.

Another problem - is NVidia. If you use card GF 9xx and higher - your only choice use 64-bit windows. Because last pae-compatible 32-bit driver was 332.21. and it support only 7xx series.

It doesn't work for Win 7 Ultimate.
Everything is patched successfully, but after reboot it goes to repair as many complained here and in other web-sites.
I suspect that some KBXXXXX update prevents this patch to work.

Hey, I tried using the patch and followed the instructions (for a 32-bits Windows 7 Ultimate SP1), but one of the command didn't work

PatchPae2.exe -type loader -o winloadp.exe winload.exe

I think it said "Failure". Though I tried all the other steps and the operations were successful. After rebooting, I could choose to boot with Win7 or Win (Patched), and chose the patched version. After that, the system tries to repair itself and get stuck on the "attempting repairs..." procedure, even when prompting "start windows normally" at startup.

If you created an patched kernel for an alternate boot option using the testsinging method instead of the winload method, then you could boot the stock kernel after the Windows Update this spring broke the patched kernel and reapply the patch without problem.

Thought I would add a clarification to the issue of PAE. PAE has been part of the Intel architecture and Windows since at least the year 2000 and is enabled automatically in Windows Server 2003. When you "patch" the kernel what you are doing is changing a function that checks to see if you are "licensed" for PAE. The idea was that PAE was part of "Enterprise" or "Datacenter" editions of Windows that cost more, even though the PAE kernel is in every edition of Windows over the past 15 years. Drivers that break PAE, like NVidia, are really implementations that break the rules of Windows 32 bit coding - any software that follows the rules will be fine with PAE. That also means that any individual application is still limited to 4GB; it is the OS that can manage against the full memory you have installed. To me it is quite annoying that MS doesn't support PAE in Windows desktop OSs as a feature - probably just because they don't want to support it in their documentation, testing, and call centers.

I first did this by hand (using a hex editor) about 3 years ago - on Win 7 SP1 on a 2006 Dell Dimension 9200. For a long time I was fine with the entire 4GB, but I recently discovered I could go double-density and now successfully run 32 bit with 8GB. This works perfectly, but periodically an update will kill it - Nvidia broke PAE last fall and I have to keep the video driver at an older version - 332.21. More recently, MS updates broke it this month and I keep KB3045685, KB3045999, and KB3022345 as hidden. When it breaks I simply boot back to 3GB and isolate what went wrong. I imagine I can re-create a PAE kernel again after applying these updates, but haven't done that yet. I've gone this route (as you likely know) because MS does not offer an upgrade path from Win 7 32 to Win 7 64 and I do not want to rebuild a machine that is the centerpiece of the house - all TV and movies run through WMC to 3 XBox extenders - and I believe I will lose all encrypted recordings (HBO and Showtime mostly) if I rebuild.

I can get through the command PatchPae2.exe -type kernel -o ntkrnlpx.exe ntkrnlpa.exe but fails each time on line PatchPae2.exe -type loader -o winloadp.exe winload.exe. I am running windows 7 Professional. Any suggestions.

This is not on a computer it's a phone you need to get the one set this up in my name and added this stuff before the phone was all the way set up I no who it is just waiting on a report then it will stop

I have an old Lenovo Thinkpad. The usable RAM in the system is limited to 3GB because of some limitation in the motherboard, even though it has a 64 bit compatible Core 2 Duo processor. Does this patch help with this problem?

Yes, you would, because the "motherboard limitation" is that Windows needs some of the 4GB of address space for a graphics framebuffer, and your video card probably uses some RAM to provide that framebuffer. Some hardware (such as PCI Express hardware, DMA buffers, etc.) also need I/O address space that can't be used for RAM.

@Suleiman,
There are instructions for enabling PAE support under Windows XP out there, but relatively few applications can take advantage of it on a desktop Windows XP machine. It might help if you regularly use more than 2GB RAM while browsing the web, but chances are that you'd be better off moving to newer hardware if you really use lots of RAM.

You were *exited* or *excited* LOL.
I would not recommend using XP on any machine, anywhere. Microsoft stopped supporting XP almost a year ago, so unless you've got a paid support account, you're not getting security patches, and antivirus vendors are slowly dropping support, so getting an up-to-date antivirus (you do use antivirus, don't you?) will start getting harder and harder.
There are a lot of cheap computers that come with Windows 7/8.1 64-bit preinstalled...dump the old hardware unless you have a need for it, or go with a Linux distro that will run on that hardware.

@likefunbutnot thank you so much for your prompt respond and the infos. In that case I will keep my babe the way it is. I don't want to make any change on it physically lol . Btw, I have high end pc with insane power on it sitting at home. But I just wanted my fist love pc to function better.

@Doc
Ya I was exited out of excitement....guess u do not have that auto correct thing and what is anti virus? lol Thanks for the feedback. Now i will let my pc retire peacefully.

At the risk of belaboring the obvious, this is a third-party tool that the author of the article is suggesting that people use to modify the deepest level of their Windows installation and further, to tell Windows to ignore its own security policies for dealing with just this sort of modification.
PAE is something I've used on Windows Server machines for ages and it is certainly a legitimate technology, but perhaps a warning to proceed at one's own risk might be in order?